The present invention relates generally to an optical fiber dispenser for a missile or other moving vehicle, and, more particularly, to an inside payout optical fiber canister.
A guided missile may remain interconnected with control apparatus upon launch by an optical fiber, over which navigational information is exchanged during at least a part of the missile travel path. The optical fiber is typically wound into an optical fiber pack carried in a canister on the missile or other vehicle, and care must be taken in the manner of paying out (dispensing) the optical fiber to avoid damaging the optical fiber.
One difficulty encountered on dispensing an optical fiber from a wound optical fiber pack, especially at the high payout speeds required for many missiles, is the tendency for the filament to form helical loops of relatively large amplitude extending transversely to the dispensing direction. Such large loops of optical fiber can produce tangling or snarling of the optical fiber, leading to breaking of the optical fiber. The presence of such large loops can also have indirect adverse consequences on the missile through their influence on its design. Large helical loops of paid out optical fiber are generally incompatible with the mounting of the engine (air breathing or rocket) in the tail of the missile, because the aft-directed engine exhaust plume is likely to impinge upon and damage the optical fiber as it swings widely behind the missile. It is therefore necessary to mount the engines in the sides of the missile, which is less efficient than a tail-mounted engine. The helical pattern traced by the optical fiber also requires a large exit port in the optical fiber canister, and prevents ducting of the optical fiber. Yet another result is that the radar cross-section of the missile (i.e., detectability) is larger than desired.
It is, therefore, highly desirable to provide an optical fiber payout technique ideally producing a linear trajectory, allowing dispense from a small exit port or duct. Payout should be accomplished without subjecting the filament to significant risk of damage, destruction or reduction in signal transmission capabilities.